Manufacture of synthetic carbolic acid.



FABTdICIUS UQBELLIS, E PHILADEL'EHIA, PENflSYLVAlQ'Li-l.

MANUFACTURE 01 SYNTHETKE CMBQZBIQ ACID.

l'io Brewing.

To all whom it may concern:

Be it known that l, Fssnrcrcs Cosntms, a subject of the Kin of Italy, and a resident of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements Heretofore synthetic carbolic acid has been manufactured b sulfonating benzol with concentrated sul uric acid, in order to obtain benzene-sulfonic acid. The mixture of sulfuric and benzene-sulfonic acids ,is then poured into Water ahd neutralized with calcium or barium hydroxid with produc tion of calcium or barium benzenosulfonato and the corresponding sulfate. The benzene-sulfonic salt is soluble, the sulfate is insoluble, so by simple filtration they are separated and carbolic acid is then produced by treating the henzene-sulfonate in the well known manner. lln this process all of the sulfuric acid is lost, being taken up in the production of calcium or barium sulfate, which are practically yalueless.

According to my invention, instead of using a calcium or barium salt, I employ a zinc compound, to neutralize the mixture of sulfuric and benzene-sulfonie acid, and thereby obtain a solution of zinc sulfate and zinc benzene-sulfonate, which when acted upon by barium sulfid' gives both barium,

benzene-sulfonate (from which carbolic acid is obtained), and also barium sulfate and zinc sulfid (which constitute the raw materials for the production of lithopone, which is a valuable product) In carrying out my process I neutralize the aqueous solution of benzene-sulfonic acid and sulfuric acid with say zinc oxid (or some other. suitable zinc compound). .1 thereby produce a solution of zinc sulfate and zinc benzene-sulfonate. By mixing" this with the calculated quantity of barium sulfid ll obtain a precipitate which. consists Specification of Letters Patent.

Patented Apr, 29, ltl'lt'l,

Application flied February 9, 1917. serial No. 147,545.

of zincsulfid and barium sulfate, leaving in solution the barium benzene-sulfonate.

The reactions take place according to the following formulae 266115SG3II+5I'LSO4+GZIIOI (C,,H,-.SO;,) Zn+5ZnSO +6H U (C H SOQ,Zn+5ZnSO,+6BaS:

(C H SOQ 1821+ (GZnS-l-SllaSOQ The solid precipitate being a mixture of zinc sulfid and uarium sulfate, is treated in the Well liDO'Wll JN'oy for the production of commercial lithtuione, a valuable and useful material in the manufacture of paints.

Carbolic acid is manufactured from barium benzenesulfonate in a well known Way, by precipitat ng the barium with sodium sulfate or sodium carbonate, in order to produce sodium-henzehe sulfonate, which is evaporated to dryness and mixed with caustic soda, producing a solid mass which is then fused to 300 degrees (3., and when the re-action is complete, neutralized with acid in order to free the carbolic acid which is distilled in cameo or with steam and allowed to crystallize.

The same method may be applied to the manufacture of resorcinol, naphthol, xylol and other homologous products, where sulfonic acid is used for sulfonation, or Whenever it is desired to introduce an OH group of a phenolic character into an aromatic hydrocarbon.

Having thus described my invention, ll claim:

/ The process of manufacturing phenol or its derivatives, and also barium sulfate and zinc sulfid, which consists in neutralizing sulfuric acid solution and benzene sulfonic acid with a zinc compound, with production of the corresponding zinc sulfate, and zinc sulfonate, adding thereto barium sulfid, whereby barium sulfate and zinc sullid are precipitated, leaving barium benzene sulfonate, and producing the desired phenol derivative therefrom.

:2. The process of manufacturing synthetic carbolic acid and lithopone, which oohsists in neutralizing a solution of benzene sulfonic acid sulfuric acid with e, aiuc till m 1,301,9oo

compound, with production of zinc sulfate signed my name, at Philadelphia, Pennsylzgnd zinc iggzenle-sufifonfite, adding thereto vsinia, this fifthday of February, 1917. arium su ,w ere yt e component arts of lithopone are precipitated, leaving bar IC C L 5v nium benzene-sulfonate in solution, and Witnesses:

producing synthetic carbolic acid. therefrom. JAMES H. BELL, In testimony whereof,- I have hereunto E. L. FULLERTON." 

